I've used a couple Dazzle products. I wasn't that impressed. This was probably about a year ago however. Most of the Apple-heads out there use this :
http://www.formac.com/p_bin/?cid=solutions_converters_studiodv I believe. It is kinda pricey, but it's supposed to work really good. I would look at it, and then find a Dazzle that compares to it. Get the Dazzle and if you don't like it, bring it back and then check out the Formac solution. There is some more stuff out there that are available, and there is a thread kickin' around that has some links in it. Try and do a search for video and capture.
Just did a quick search and came up with the Canopus line of stuff :
http://www.canopus.com. They are very expensive though, from memeory, but their stuff is supposed to be "studio" quality stuff.
Hope this helps...
EDIT: One last thing. Whatever you choose to get, make sure you get FireWire. You do NOT want to be doing video transfer with USB. It will work, but it will take forever. Only the really new Macs come with USB2 so there is no use looking at anything USB. Just took a quick look at the eMac specs, and none of them come with USB2. So FireWire is your friend here.
OffTopic : Do you love your eMac or what? I'd get one just to have one
They are really nice.